Program to implement Inverse Interpolation using Lagrange Formula | C # code for solving inverse interpolation ; Consider a structure to keep each pair of x and y together ; Function to calculate the inverse interpolation ; Initialize readonly x ; Calculate each term of the given formula ; Add term to readonly result ; Driver Code ; Sample dataset of 4 points Here we find the value of x when y = 4.5 ; Size of dataset ; Sample y value ; Using the Inverse Interpolation function to find the value of x when y = 4.5
using System ; class GFG { class Data { public double x , y ; public Data ( double x , double y ) { this . x = x ; this . y = y ; } } ; static double inv_interpolate ( Data [ ] d , int n , double y ) { double x = 0 ; int i , j ; for ( i = 0 ; i < n ; i ++ ) { double xi = d [ i ] . x ; for ( j = 0 ; j < n ; j ++ ) { if ( j != i ) { xi = xi * ( y - d [ j ] . y ) / ( d [ i ] . y - d [ j ] . y ) ; } } x += xi ; } return x ; } public static void Main ( String [ ] args ) { Data [ ] d = { new Data ( 1.27 , 2.3 ) , new Data ( 2.25 , 2.95 ) , new Data ( 2.5 , 3.5 ) , new Data ( 3.6 , 5.1 ) } ; int n = 4 ; double y = 4.5 ; Console . Write ( " Value ▁ of ▁ x ▁ at ▁ y ▁ = ▁ 4.5 ▁ : ▁ { 0 : f5 } " , inv_interpolate ( d , n , y ) ) ; } }